1. Technical Field
This invention relates to manufacture of articles, especially laminar, shaped articles of a heterogeneous blend of (a) a polyolefin and (b) a barrier resin comprising a blend of two polymers; and to such articles especially in the form of barriers to permeation of fluid, liquid and gaseous materials.
2. Background Art
U.S. Pat. No. 4,410,482 discloses a process for manufacturing a laminar, shaped article of polymeric material comprising the steps of establishing a melted, heterogeneous, blend of a polyolefin, a condensation polymer such as a polyamide, and a compatibilizer; and forming the melted blend by stretching a body of the melt and cooling the stretched body to below the melting point of the lowest melting polymer component. Such laminar articles are useful as containers for liquid hydrocarbons, including fuel tanks for motor vehicles.
U.S. Pat. No. 4,410,482 also discloses laminar shaped articles based on such blend wherein the polyolefin and the polyamide are present in the article as a multitude of thin, substantially two-dimensional, parallel and overlapping layers of material. The barrier properties of such articles are good but not sufficient to satisfy current commercial and regulatory requirements for barriers to permeation of fluid, liquid and/or gaseous materials. An article is therefore needed which provides improved barrier properties while maintaining the advantages of prior art articles.